There is national recognition of the need to incorporate Aboriginal health issues within the medical school curricula. This study aims to evaluate changes in medical students’ knowledge and attitudes about Aboriginal health, and their preparedness to work in Aboriginal communities after attending a 3-hour Aboriginal health seminar. A cross-sectional survey was administered before and after the seminar for Year 1 and 2 medical students at the University of Western Ontario. The survey included four true or false questions and 24 questions using a seven-point Likert scale (1 – strongly disagree, 7 – strongly agree). Eighty two of 130 (64 per cent) Year 1 students and 55 of 86 (63 per cent) Year 2 students completed both questionnaires. Knowledge-based questions were answered correctly by most students before the seminar, with an increasing number of correct responses noted after the seminar (p < 0.05). Students’ perceptions about sociocultural and economic factors affecting health showed uncertainty before the seminar, but changed towards greater agreement regarding its impact on health after the seminar (p < 0.05). Students initially felt unprepared to care for Aboriginal patients before the seminar, but felt more prepared after the seminar (p < 0.05). A 3-hour seminar using both didactic and non-traditional teaching methods appears to be effective in the short term in improving knowledge, changing attitudes and reversing some of the uncertainties medical students have about practicing in Aboriginal communities.